Art of distilling petroleum-oils



F. B. LEWIS AND T. S. COOKE.

ART OF msmuwe PETROLEUM OILS.

APPLICATION FILED MAY 7, 191?.

Patented Oct. 4, 1921.

a mm L 5 i a UNITED STATES FRANK B. LEWIS AND THOMAS S. STANDARD OILCOMPANY, OF DIANA.

PATENT OFFICE.

AB'I OF DISTILLING PETROLEUM-OILS.

Specification of Letters Patent.

Patented Oct. 4, 1921.

Application filed Kay 7, 1917. Serial No. 166,965,

To all whomitmay concern:

Be it known that we, FRANK B. LEVIS and THOMAS S. Coons, citizens of theUnited States, residing at \Vhiting, in the county of Lake and State ofIndiana, have invented a new and useful Improvement in the Art ofDistilling Petroleum-Oils, of which the following is a specification.

Our invention relates to the art of distilling petroleum oils and moreparticularly to a process, of distillation conducted under pressure'forthe purpose of effecting the conversion of heavier or high boiling pointoils into lighter or lower boiling point oils, as is more fullydescribed in the patent to m. M. Burton, No. 1,049,667.

We have discovered that a distillation process of this character may beaccelerated and made to yield superior results both quantitatively andqualitatively if the vapors passing from the still are subjected to theabsorbing or direct condensing action of a body or bodies of liquid, asfor exam 1c in a fractionating column or the like. l 3y the use of sucha fractionating means there are condensed from the outgoing vapor streampractically all constituents thereof which have not suffered sufficientdecomposition, and at the same time the condensing effect is soperfectly controlled that no substantial proportion of the vapors whichhave suffered sufficient decomposition is condensed. In practice weprefer to connect the inlet end of the fractionating column or itsequivalent directly with the still, so that the refluxing condensate mayreturn immediately and continuously to the still. "e also pre ortoconnect the vapor outlet at the top of the fract-ionating column orits equivalent, through .an open pipe, directly with a water cooledcondenser in which the vapors constituting the net result of the processare condensed under the same pressure obtaining in the still and itsconnecting fractionatin column.

Tlie invention will be fully understood from the following detaileddescription of one method of carrying out the same. In this description,reference will be had to the accompanying drawing which illustrates moreor less diagrammatically an arrangement of still, fractionating columnand final condenser, which we find well suited to the practice of ourinvention.

In this drawing the numeral 1 designates atinc column illustrated in thedrawing is of the outline of a vertical cylinder having arranged in itsinterior a plurality of pans 6, each of which is provided with vaporducts 7 capped by heads 8 which are perforated at their side walls nearthe bottom of the pan. A constant level of liquid is maintained in eachpan by means of an overflow pipe 9 which discharges into the next lowerpan. The bottom pan designated 6 is spaced some little distance abovethe lower end of the column, and the overflow pipe 9 for this pancarries an inverted siphon or trap 10. The reflux condensate collectingin the bottom of the column is returned to the still by a drain pipe 11tapped into the back head of the still and connect ing within the stillwith an inverted siphon 12 (shown in dotted line) by which the refluxcondensate is carried down near the hot bottom of the still and againbrought upwardly and discharged into the upper portion of the still at apoint above the average liquid level and not substantially below thehighest liquid level therein.

From the upper end of the fractionating column the outgoing vapors arecarried through a line 13 to a condensin coil 14 mounted in a water bath15. This coil drains into a receiving drum 16 provided at the bottomwith a li uid drawofl pipe 17 and at the top with a va ved gas-escapeand control pipe 18.

I The operation of this apparatus is as folows:

A charge of relatively heavy or high boiling hydrocarbon oils from whichit is desired to produce a maximum quantity of relatively low boilingpoint or li ht hydrocarbons, is introduced into the stifi 1 and by meansof the furnace 2 the contents of the still are raised to the temperatureat which distillation begins. It may be noted that in order to preventthe distillation of an part i of the charge contained within the stil 1before the desired operating temperature has been reached. it is ofadvantage to introduce into the still and condenser system, as for.

instance through the gas pipe 18, an -incon- I densable and chemicallyinert gas in suflicient quantities to create a substantial pressurewithin the apparatus; An economical method of effecting this result isfully described in the atent to Edgar M. Clark No. 1,129,034. f thestill and condenser system be thus charged with gas under pressure, theliquid body within the still is prevented from distilling over until ithas been raised in temperature to the point required to begin theconversion. lVhen this temperature (which is dependent u on the pressuremaintained in the apparatus? is attained the liquid contents of thestill begin to suffer chemical changes by which they are in partconverted into lighter and lower boiling point constituents, and suchreaction products accompanied and diluted by a greater or lessproportion of vapors which have not been decomposed to the full extentdesired, pass out through the vapor line 3 and into the base of thefractionating column 4. In their passage upward through the column thesevapors are fractionally condensed, the condensate serving to fill thepans 6 and continuously overflowing from each upper pan to the nextlower pan and finally into thebase of the column, from which thecondensate drains through the pipe 11 back to the still 1. Byreason ofthe inverted siphon 12 this reflux condensate becomes heated to thetemperature existing in the still by being carried through the liquidbody therein and is then discharged near the top of the still. Shouldthere be any water in the reflux condensate it is therefore introducedin such a manner as to avoid thumping.

Vhen the series of pans 6 in the fractionating column 4 has becomefilled with liquid the outgoing vapors are compelled to bubble throughthe liquid in these pans successively in order to reach the top of thecolumn. The pans and the liquid bodies therein are automaticallymaintained at progressively decreasing temperatures from the base to thetop of the column, and the condensate in each pan is of correspondinglydilferent gravity and boiling point. By reason of the thorough-washingand extensive surface contact of the vapors with the several liquidbodies, we find that there is effected an exceedingly accuratefractionation. The column is so proportioned and its condensing capacityis such that the liquid body in the lower pan 6 does not at any time inthe normal operation of the apparatus contain any appreciable proportionor percentage of the low boiling point or light constitutents which areto constitute the net resultof the process, so, also the contents of thetop an 6 will be substantially an oil slightlyhi er in boilingpoint thanthe end ractions of the resu t of the process. The intermediate roductwhich is to constitute the net p to aaim all novelty inherent in ourinvert-- pans will contain in varyi proportions, heav and light or highboiling point and low oiling point fractions or constituents.

The vapors which escape condensation in the column 4 or which areredistilled from the upper pan 6 thereof, pass outwardly through theline 13 and are condensed in the water cooled condenser 14, drainingfrom the latter into the receiving drum 16 from which they are withdrawnat such a rate as to maintain a free space above the liquid level in thedrum.

The pressure within the a paratus will be controlled through the s pipe18, this pipe serving to vent from tfi: system any excess quantity ofincondensable gas formed therein, or to convey into the systemincondensable gas from some other source should the production of gaswithin the system fail at any time to answer the predetermined pressurerequirements therein. A simple method of accomplishing this pressurecontrol through the as-escape pipe 18 is illustrated and descri ed inthe patent to Edgar M. Clark above referred to.

The process heretofore described isof the greatest technical advantagewhenapplied to the pyrogenesis of gasolene, i. e., themixture ofaliphatic hydrocarbons mainly of the saturated series and boilingbetween 80 and 400 to 420 F., from the heavier or higher boiling pointconstituents of crude petroleum. such as fuel oil. gas oil and the otherrelatively heavy products or residues of refinery processes boiling inlarge part at and above 500 F.

As a specific example of the process above described the following maybe given:

A still of a capaclty of 200 barrels is provided with a fractionatingcolumn of the design shown in the drawing, 6 feet in diameter and 30feet in height and provided in its interior with 20 pans, the li uiddepth in each pan being 6 inches. is still is char d with a petroleumoil or troleum resi ue, the fractions of which boll between 450 and 750F., the mixture having a Baum gravity of about 30. The distillation isconducted under a pressure of 5} atmospheres.

While we have described in considerable detail the s ific form ofapparatus which we find wel adapted to the carrying out of our improvedprocess, as well as the details of a particular commercial process in'ac-' cordance with the invention, it will be understood that this isillustrative only and for the purpose of makin clear the nature and modeof applying invention and that the invention s not to be regarded aslimited in scope to the illustrative details given except in so far assuch limitation 'is included within the terms of the nonbinclaims inwhich it is our'inlfiention ficiently and maintained cracked Vapors tionas broadly as is permissible in view of t e prior art.

hat We claim as new and desire to secure by Letters Patent is- Theimprovement in the art of cracking petroleum oils by distillation underpressure which consists in passing the mixture of sufficiently crackedand insufficiently cracked vapors continuously produced within the stillthrough a plurality of separated bodies of petroleum oil arranged inseries at temperatures such as to condense all insufficiently crackedfractions but not to condense the sufficiently cracked fractions, andcondensing and collecting the sufficiently crackedfractions which escapecondensation in the said liquid bodies.

2. he improvement in the art ofcracking petroleum oils by distillationunder pressure which consists in passing the mixture of sufficientlycracked and insufficiently continuously produced within the stillthrough a plurality of separated bodies of petroleum oil arranged inseries and maintained at tem eratures such as to condense allinsufficient y cracked fractions but not to condense the sufficientlycracked fractions, condensing and collecting the sufcracked fractionswhich escape condensation in the said liquid bodies, and continuouslyreturning to the still the insufficiently cracked fractions condensed bythe said liquid bodies.

3. T e improvement in the art of cracking :petroleum oils.by.distillation under pressure which consists in passing the mixture ofsufficiently cracked and insufliciently cracked vapors continuouslyproduced within the still through a succession of liquid bodies ofpetroleum oil maintained at temeratures such as to condense allinsufliciently cracked vapors but not to condense the suflicientlycracked fractions, the said liquid bodies being connected anddischarging one into the other, in a direction opposite to the flow ofvapors, and separatel condensing and collecting the sufficient y crackedfractions escaping condensation in said liquid bodies.

4. The improvement in the art of producing gasolene hydrocarbons fromrelatively heavy hydrocarbons which consists in subjecting suchrelatively heavy hydrocarbons to distillation under a pressure upward of4 atmospheres, passing the mixture of sufficiently and insufficientlycracked vapors continuously produced within the still the su liquidbodies being connected and dischargthrough a succession of liquid bodiesof petroleum oil maintained at temperatures to condense allnon-gasolenelike hydrocarbons and not to condense the gasolenelikehydrocarbons, and separately condensing and collecting the gasolenelikehydrocarbons.

5. The improvement in the art of roduc ing gasolene hydrocarbons from reatively heavy hydrocarbons which consists in subjecting such relativelyheavy hydrocarbons to distillation under a pressure upward of 4atmospheres, passing the mixture of sufficiently and insufficientlycontinuously produced within the still through a succession of liquidbodies of petroleum oil maintained at temperatures to condense allnon-gasolenelike hydrocarbons and not ta condense the gasolenelikehydrocarbons, separately condensing and collecting the gasolenelikehydrocarbons, and continuously returning the condensed nongasolenelikehydrocarbons to the still.

6. The improvement in the art of crack ing petroleum oils bydistillation under pressure which consists in passing the mixture ofsufliciently cracked and insufficiently cracked vapors continuouslyproduced Within the still through a succession of liquid bodies ofpetroleum oil maintained at temperatures such as to condense allinsufficientl cracked vapors but not to condense ciently crackedfractions, the said 111g one' into the other in a direction opposite tothe flow of vapors, separately condensing and collecting thesufficiently cracked fractions escaping condensation in said liquidbodies, and maintaining the entire system, including the final condenserfor the cracked fractions under the same ressure.

7. The improvement in the art 0 producing gasolene hydrocarbons fromrelatively heavy hydrocarbons which consists in subjecting suchrelatively heavy hydrocarbons to distillation under a ressure upward offour atmospheres causm" the vapors of the sufficiently cracked fractionsto pass through a plurality of separated bodies of petroleum oilarranged in a series'maintained at successively lower temperatures, thatof the final body being sufficient to pass the asolene of the desiredconstitution and condensing and collecting the fractions which passthrough said liquid bodies.

FRANK B. LEWIS. THOMAS'S. COOKE.

cracked vapors DISOLAIMEQB 1,392,584.-Frank B. Lewis and Thomas S.Cooke, Whiting, Ind.; An or Dxs'rnmmp Pmonbnu 0114!. Patent datedOctober 4, 1921. Diacla-nmer filod Apnl 18, 1936, by the assignee,Slandani Oil Company.

'Hcrcby en'tera this disclaimer to that part of the specification whichconstitutes claima1,34,56and7.

idpwi dud, May 1:, 1936.]

